Refers to someone (usually a man) who, a lot like the most interesting man in the world from the XX commercials, purports to be able to have grandiose powers and do things that one else can. Can be both positive or negative depending on how the phrase is used. In the positive, it is a compliment to someone's ability; in the negative it is a tongue in cheek statement, that's really meant to slight someone as not being capable of anything like he purports himself to be capable of.

Positive example: Ya, that guy is a real a bulldog. Some people may be able to kill two birds with one stone- but this guy kills all birds with two stones. The ones in his pants.

Negative example: Ya that lawyer doing the commercials on TV, I wouldn't believe shit he says. I mean, he doesn't just kill two birds with one stone. He's killing all birds with two stones. The ones in his pants.